
<!DOCTYPE html>
<html lang="en">
<head>
	<meta charset="UTF-8">
	<title>CSS3 边框</title>
	<style>
		body, ul, li, dl, dt, dd, h1, h2, h3, h4, h5 {
			margin: 0;
			padding: 0;
		}

		body {
			background-color: #F7F7F7;
		}

		.wrapper {
			width: 1000px;
			margin: 0 auto;
			padding: 20px;
			box-sizing: border-box;
		}

		header {
			padding: 20px 0;
			margin-bottom: 20px;
			text-align: center;
		}

		header h3 {
			line-height: 1;
			font-weight: normal;
			font-size: 28px;
		}

		.main {
			/*overflow: hidden;*/
		}

		.main:after {
			content: '';
			clear: both;
			display: block;
		}

		.main .item {
			width: 210px;
			height: 210px;
			margin: 0 30px 30px 0;
			display: flex;   /*可以自动居中*/
			position: relative;
			background-color: #FFF;
			float: left;
			box-shadow: 2px 2px 5px #CCC;
		}
		
		.main .item:after {
			content: attr(data-brief);
			display: block;
			width: 100%;
			height: 100%;
			text-align: center;
			line-height: 210px;
			position: absolute;
			top: 0;
			left: 0;
			color: #FFF;
			font-family: '微软雅黑';
			font-size: 18px;
			background-color: rgba(170, 170, 170, 0);
			z-index: -1;
			transition: all 0.3s ease-in;
		}

		.main .item:hover:after {
			background-color: rgba(170, 170, 170, 0.6);
			z-index: 100;
		}

		.main .item:nth-child(4n) {
			margin-right: 0;
		}

		.main .item:nth-last-child(-n+5) {
			margin-bottom: 0;
		}

		/* 以上是骨架样式 */
		.border-radius{
			width: 180px;
			height: 180px;
			border: 1px solid red;
			margin: auto;
			/*第一个参数是左上角-然后顺时针*/
			/*border-radius:50%*/
		}
		/*圆形*/
		.item:nth-child(1) .border-radius{
			border-radius: 50%;
		}
		
		/*拱形*/	
		.square{
			width: 180px;
			height: 180px;
			border: 1px solid red;
			margin: auto;
			/*第一个参数是左上角-然后顺时针*/
			border-radius:90px 90px 0px 0px ;
		}
		/*半圆*/
		.item:nth-child(3) .border-radius{
			height: 90px;
			border-radius: 90px 90px 0 0;
		}
		.item:nth-child(4) .border-radius{
			border-radius: 90px 0px 0px 0px;
		}
		/*四分之一的圆*/
		.item:nth-child(5) .border-radius{
			height: 90px;
			width: 90px;
			border-radius: 90px 0px 0px 0px;
		}
		/*横着的椭圆*/
		.item:nth-child(6) .border-radius{
			height: 90px;
/*			border-radius: 50%; 百分比表示*/
			border-radius: 90px/45px; /*将长轴设置为90,短轴设置为45,多出的地方无所谓*/			
			
		}
		/*竖着的椭圆*/
		.item:nth-child(7) .border-radius{
			width: 90px;
			border-radius: 45px  / 90px ;	
			/*4个45 4个90*/	
		}
		/*半个横着的椭圆*/
		.item:nth-child(8) .border-radius{
			height: 45px;
			border-radius: 90px 90px 0px 0px /45px 45px 0px 0px;			
		}
		
		/*半个竖着的椭圆*/
		.item:nth-child(9) .border-radius{
			width: 45px;
			border-radius: 45px 0px 0px 45px /90px 0px 0px 90px;			
		}
		
		/*四分之一竖着的椭圆*/
		.item:nth-child(10) .border-radius{
			width: 45px;
			height: 90px;
			border-radius: 45px 0px 0px 0px /90px 0px 0px 0px;			
		}
		/*饼环*/
		.item:nth-child(11) .border-radius{
			width: 40px;
			height: 40px;
			border: 70px solid red;
			border-radius: 90%;
		}
		/*当圆角的半径小于等于边框宽度时，元素内角是直角*/
		/*圆饼*/
		.item:nth-child(12) .border-radius{
			width: 40px;
			height: 40px;
			border: 70px solid red;
			border-radius:70px;
		}
		/*左上角圆饼*/
	   	.item:nth-child(13) .border-radius{
	   		width: 40px;
	   		height: 40px;
	   		border:70px solid red;
	   		border-radius: 40px 0px 0px 0px;
	   	}
	   	/*对角圆饼*/
	   	.item:nth-child(14) .border-radius{
	   		width: 40px;
	   		height: 40px;
	   		border:70px solid red;
	   		border-radius: 90px 0px 90px 0px;
	   	}
	   	 /*四边不同色*/
	   	.item:nth-child(15) .border-radius{
	   		width: 0px;
	   		height: 0px;
	   		border:90px solid red;
	   		border-color: blue  red teal yellow;
		   	}
		 /*四边的右边透明*/
	   	.item:nth-child(16) .border-radius{
	   		width: 0px;
	   		height: 0px;
	   		border:90px solid red;
	   		border-color: blue  red teal transparent;
		   	}
		/*圆右透明*/
	   	.item:nth-child(17) .border-radius{
	   		width: 0px;
	   		height: 0px;
	   		border:90px solid red;
	   		border-radius: 90px;
	   		border-color: blue transparent  red teal ;
		   	}
		/*圆右不透明*/
	   	.item:nth-child(18) .border-radius{
	   		width: 0px;
	   		height: 0px;
	   		border:90px solid red;
	   		border-radius: 90px;
	   		border-color:  transparent red  transparent transparent ;
		   	}
		/*阴阳*/
	   	.item:nth-child(19) .border-radius{
	  		width: 180px;
			height: 0px;
			border-top-width: 90px;
			border-bottom-width: 90px;
			border-style: solid;
			border-top-color: red;
			border-bottom-color: green;
			/*border-right-color: red;*/
			border-radius: 90px;
		   	}
		/*阴阳图前世2*/
		.item:nth-child(20) .border-radius {
			width: 180px;
			height: 90px;
			border-bottom-width: 90px;
			border-style: solid;
			border-bottom-color: green;
			background-color: red;
			/*border-right-color: red;*/
			border-radius: 90px;
		}
		
		/*阴阳图今生*/
		.item:nth-child(21) .border-radius {
			width: 180px;
			height: 90px;
			border-bottom-width: 90px;
			border-style: solid;
			border-bottom-color: green;
			background-color: red;
			border-radius: 90px;
			position: relative;
		}
		.item:nth-child(21) .border-radius::after,
		.item:nth-child(21) .border-radius::before {
			content: '';
			position: absolute;
			top: 50%;
			width: 20px;
			height: 20px;
			/*margin: -10px 0 0 0;*/
			border-width: 35px;
			border-style: solid;
			/*border-radius: 45px;*/
		}
			/*左阴阳*/
		.item:nth-child(21) .border-radius::after {
			background-color: red;
			border-color: green;
			border-radius: 50%;
		}
		/*右阴阳*/
		.item:nth-child(21) .border-radius::before {
			background-color: green;
			border-color: red;
			border-radius: 50%;
			right: 0;
		}
		/*消息框*/
		.item:nth-child(22) .border-radius {
			width: 160px;
			height: 80px;
			background-color: red;
			border-radius: 6px;
			position: relative;
		}
		
		.item:nth-child(22) .border-radius::before{
			content:"";
			width: 0px;
			height: 0px;
			border-width: 10px;
		    border-style: solid;
		    border-color:transparent  red  transparent transparent;
		    top: 28px;
		    left: -20px;
		    position: absolute;
		    
		   
		}
		/*奇怪的图形*/
		.item:nth-child(23) .border-radius {
			width: 40px;
			height: 40px;
			border-width: 45px 0px 45px 70px;
			border-style: solid;
			border-radius: 0 0 60px 0;
			border-color: red;
	   
		}
		/*奇怪的图像2*/
		.item:nth-child(25) .border-radius {
			width: 100px;
			height: 40px;
			border-width: 45px 20px 45px 70px;
			border-style: solid;
			border-radius: 60px;
			border-color: red;
		}
				/*QQ对话*/
		.item:nth-child(26) .border-radius {
			width: 160px;
			height: 80px;
			background-color: red;
			border-radius: 6px;
			position: relative;
		}

		.item:nth-child(26) .border-radius::after {
			content: '';
			position: absolute;
			top: 0;
			right: -20px;
			width: 30px;
			height: 30px;
			border-style: solid;
			border-width: 0 0 30px 30px;
			border-radius: 0 0 60px 0;
			border-bottom-color: red;
			border-left-color: transparent;
		}

		
		
		
	</style>
</head>
<body>
	<div class="wrapper">
		<header>
			<h3>CSS3 边框圆角</h3>
		</header>
		<div class="main">
			<div class="item" data-brief="整圆">
				<div class="border-radius"></div>
			</div>
			<div class="item" data-brief="拱形">
				<div class="square"></div>
			</div>
			<div class="item" data-brief="半圆">
				<div class="border-radius"></div>
			</div>
			<div class="item" data-brief="左上角">
				<div class="border-radius"></div>
			</div>
			<div class="item" data-brief="四分之一圆">
				<div class="border-radius"></div>
			</div>
			<div class="item" data-brief="横着的椭圆">
				<div class="border-radius"></div>
			</div>
			<div class="item" data-brief="竖着的椭圆">
				<div class="border-radius"></div>
			</div>
			<div class="item" data-brief="半个横着的椭圆">
				<div class="border-radius"></div>
			</div>
			<div class="item" data-brief="半个竖着的椭圆">
				<div class="border-radius"></div>
			</div>
			<div class="item" data-brief="四分之一竖着的椭圆">
				<div class="border-radius"></div>
			</div>
			<div class="item" data-brief="饼环">
				<div class="border-radius"></div>
			</div>
			<div class="item" data-brief="圆饼">
				<div class="border-radius"></div>
			</div>
			<div class="item" data-brief="左上角圆饼">
				<div class="border-radius"></div>
			</div>
			<div class="item" data-brief="对角圆饼">
				<div class="border-radius"></div>
			</div>
			<div class="item" data-brief="四边不同色">
				<div class="border-radius"></div>
			</div>
			<div class="item" data-brief="右透明色">
				<div class="border-radius"></div>
			</div>
			<div class="item" data-brief="圆右透明色">
				<div class="border-radius"></div>
			</div>
			<div class="item" data-brief="圆右红透明色">
				<div class="border-radius"></div>
			</div>
			<div class="item" data-brief="阴阳图前世">
				<div class="border-radius"></div>
			</div>
			<div class="item" data-brief="阴阳图前世2">
				<div class="border-radius"></div>
			</div>
			<div class="item" data-brief="阴阳图今生">
				<div class="border-radius"></div>
			</div>
					<div class="item" data-brief="消息框">
				<div class="border-radius"></div>
			</div>
			<div class="item" data-brief="奇怪的图形">
				<div class="border-radius"></div>
			</div>
			<div class="item" data-brief="奇怪的图形2">
				<div class="border-radius"></div>
			</div>
			<div class="item" data-brief="QQ对话">
				<div class="border-radius"></div>
			</div>
			<div class="item" data-brief="圆角百分比">
				<div class="border-radius"></div>
			</div>
		</div>
	</div>

</body>
</html>